The present invention relates to stable, preferably clear, aqueous odor absorbing compositions, articles of manufacture and/or method for use on inanimate surfaces, i.e., not for use directly on human skin, as an odor-absorbing composition. Such compositions can optionally provide a "scent signal" in the form of a pleasant odor which signals the removal of the malodor. Preferably, the compositions are sprayed onto fabrics, particularly clothes, to restore their freshness by reducing malodor without washing or dry cleaning. The compositions are preferably not used directly on human skin because the preferred preservative may cause skin irritation. Fabrics treated with some preferred compositions of the present invention can also optionally provide release of fragrance upon rewetting, such as when the wearer perspires. This phenomenon provides an added benefit to fabrics treated with the composition of the present invention in that the fabrics will stay fresher longer.
A wide variety of deodorizing compositions are known in the art, the most common of which contain perfumes to mask malodor. Odor masking is the intentional concealment of one odor by the addition of another. The control of odor on fabrics, in particular clothes, has been accomplished by using perfumes, colognes, etc. However, preference to perfume is greatly varied and high levels are needed to ensure that the malodor is no longer noticeable.
Odor modification, in which the odor is changed, e.g., by chemical modification, has also been used. Current malodor modification methods known in the art are oxidative degradation, which uses oxidizing agents such as oxygen bleaches, chlorine, chlorinated materials such as sodium hypochlorite, chlorine dioxide, etc., and potassium permanganate to reduce malodor, and reductive degradation which uses reducing agents such as sodium bisulfite to reduce malodor. Both of these methods are unacceptable for general use on fabric because they can damage colored fabrics, specifically, they can bleach and/or discolor colored fabrics.
Other methods of odor control utilize actives that are targeted to react with malodors having specific chemical functional groups. Examples of such actives are; biguanide polymers, which complex with organic compounds containing organically bound N and/or S atoms and fatty alcohol esters of methyl methacrylic acid which react with thiols, amines, and aldehydes. Such actives are limited in the scope of protection which they afford because they only react with limited types of malodor. A more detailed description of these methods can be found in U.S. Pat. Nos.: 2,544,093; 3,074,891; 4,818,524; and 4,946,672; and U.K. Pat. App. No. 941,105, all of said patents and applications incorporated herein by reference.
Other types of deodorizing compositions known in the art contain antibacterial and antifungal agents which regulate the malodor-producing microorganisms found on the surface to which the deodorizing composition is directed. Many skin deodorant products use this technology. These compositions are not effective on malodors that have already been produced and malodors that do not come from bacterial sources, such as tobacco or food odors.
Fabric malodor is most commonly caused by environmental odors such as tobacco odor, cooking and/or food odors, or body odor. The unpleasant odors are mainly organic molecules which have different structures and functional groups, such as amines, acids, alcohols, aldehydes, ketones, phenolics, polycyclics, indoles, aromatics, polyaromatics, etc. They can also be made up of sulfur-containing functional groups, such as, thiol, mercaptan, sulfide and/or disulfide groups.
It is preferable to apply an odor absorbing material, preferably a broad spectrum odor absorbing material, to fabrics rather than a masking or chemical reaction material for odor control between washing and dry cleaning operations. As opposed to a masking or chemical reaction material, an odor absorbing material can eliminate a broad spectrum of odoriferous molecules and usually does not contribute an odor of its own. The commonly known solid odor absorbers such as activated charcoal and zeolites can be harmful to fabrics and therefore are not preferred as an odor controlling agent under these circumstances. Activated charcoal easily stains light colored fabrics and zeolites are seen as a light colored stain on dark colored fabrics. Furthermore, zeolites can cause "harsh" feel if too much is deposited.
Uncomplexed cyclodextrin molecules, which are made up of varying numbers of glucose units provide the absorbing advantages of known absorbent deodorizing compositions without harmful effects to fabrics. While cyclodextrin is an effective odor absorber, some small molecules are not sufficiently absorbed by the cyclodextrin molecules because the cavity of the cyclodextrin molecule may be too large to adequately hold the smaller organic molecule. If a small sized organic odor molecule is not sufficiently absorbed into the cyclodextrin cavity, a substantial amount of malodor can remain. In order to alleviate this problem, low molecular weight polyols can be added to the composition to enhance the formation of cyclodextrin inclusion complexes.
Uncomplexed cyclodextrin molecules, which are made up of varying numbers of glucose units provide the absorbing advantages of known absorbent deodorizing compositions without harmful effects to fabrics. The current teachings in the art suggest that cyclodextrin does not contribute to the growth of microorganisms despite the fact that they are made up of varying numbers of glucose units. See Effect of Hydroxypropyl-B-cyclodextrin on the Antimicrobial Action of Preservatives, S. J. Lehner, B. W. Miller and J. K. Seydel, J. Pharm. Pharmacol 1994, 46:p.188 and Interactions Between P-Hydroxybenzoic acid Esters and Hydroxypropyl-B-Cyclodextrin and Their Antimocrobial Effect Against Candida Albicans, S. J. Lehner, B. W. Miller and J. K. Seydel. It has been discovered, however, that cyclodextrin is a prime breeding ground for certain microorganisms, especially when in aqueous compositions. This growth problem leads to a problem with storage stability of cyclodextrin solutions for any significant length of time. Contamination by certain microorganisms, can cause microbial growth resulting in an unsightly and/or malodorous solution. Because microbial growth in cyclodextrin solutions can occur, it is preferable to include a water-soluble antimicrobial preservative, which is effective for inhibiting and/or regulating microbial growth, to increase storage stability of clear, aqueous odor-absorbing solutions containing water-soluble cyclodextrin.